As simple it appears to be on the paper, nulling interferometry is a difficult technique when experimentally implemented to reach high rejection factors. In that case, each defect of the system is a possibility to bring back on the detector, the photons we want to eliminate. The loss in terms of S/N ratio is quickly important. In this paper, I develop present state of the art in nulling interferometry field and experimental realisations. I describe their performance and limitations, and present technological developments all arounf the world. Particularly, I emphasize present development regarding to optical functions in the infrared spectral range (delay lines, achromatic phase shifters, beam combiners...).